1. Field of the Invention
The invention generally relates to the handling of a combined attach or Routing Area Update (RAU) procedure, and more particularly, to mobile communication devices and methods for handling a combined attach or RAU procedure which is successful for Packet-Switched (PS) domain services only.
2. Description of the Related Art
In a typical mobile communications environment, a Mobile Station (MS) (or called User Equipment (UE)), such as a cell phone, may communicate voice and/or data signals with one or more service networks. The wireless communications between the UE and the service networks may be in compliance with various wireless technologies, such as the Global System for Mobile communications (GSM) technology, General Packet Radio Service (GPRS) technology, Enhanced Data rates for Global Evolution (EDGE) technology, Wideband Code Division Multiple Access (WCDMA) technology, Code Division Multiple Access 2000 (CDMA-2000) technology, Time Division-Synchronous Code Division Multiple Access (TD-SCDMA) technology, Worldwide Interoperability for Microwave Access (WiMAX) technology, Long Term Evolution (LTE) technology, LTE-Advanced technology, and others.
Taking the WCDMA technology in compliance with the 3GPP TS 24.008 specification, v11.3.0 (referred to herein as the TS 24.008 specification) as an example, a service network supporting the WCDMA technology (referred to herein as a WCDMA network) may include a Circuit-Switched (CS) domain and a Packet-Switched (PS) domain which are responsible for providing CS domain services and PS domain services, respectively. For signaling efficiency, an MS may performed a combined attach procedure or a combined RAU procedure with a WCDMA network which operates in the Network Mode of Operation (NMO) I, to simultaneously register to both of the CS and PS domains of the WCDMA network, thereby obtaining the CS and PS domain services. However, the combined attach or RAU procedure may be successful for the GPRS services (i.e., the PS domain services) only. In such a case, the MS will keep retrying the combined attach or RAU procedure, hoping to obtain the CS domain services, and the retrying of the combined attach or RAU procedure for the CS domain services only will increase PS signaling which may lead to congestion in the PS domain of the WCDMA network.